But he avoided, as he has numerous times in the past, answering the question about when Virgin Galactic will begin its first suborbital spaceflight with passengers. Instead, he deferred to Virgin Group founder Richard Branson, who didn't attend the symposium. Whitesides said he leaves the public statements about timelines to Branson.

Virgin Galactic is the main tenant at the state of New Mexico-owned Spaceport America in southeastern Sierra County. Delays in the development of the company's two vehicle system, particularly a fatal crash in October 2014, have meant that paying passengers have yet to be transported to suborbital space from southern New Mexico. More than a decade ago, the company had initially stated a much faster timeline for the start of flights, as it petitioned New Mexico taxpayers to allocate the money for the $200 million-plus spaceport.

Making progress

Still, Whitesides said, Virgin Galactic is making progress in the testing of its SpaceShipTwo, the passenger spacecraft that's carried aloft by a plane, released and then is propelled by rocket into suborbital space.

The company's current spaceship, known as Unity, has carried out 14 test flights so far. The most-recent three involved rocket power, in contrast to previous flights that entailed the spaceship simply gliding back to the ground. The last test flight took place in July.

"You'll see at least one more flight before the end of the year," he told the audience of more than 100 people, who gathered at the New Mexico Farm & Ranch Heritage Museum for the symposium.

The next stage of spaceship testing will entail longer rocket "burns" and faster speeds, Whitesides said.

"We'll get to see exciting things as we go onto the next phase of the test flight program," he said.

Virgin Galactic officials have said repeatedly they won't launch suborbital passenger flights until the two-vehicle system has been fully tested and deemed safe.

In addition, two more spaceships are in the process of being constructed, Whitesides said.

At a tipping point

In his speech, Whitesides also highlighted the recent completion of a paved southern road to Spaceport America. Local officials have said the road is important because it dramatically cuts the driving time from Las Cruces to the remote facility and will boost the economic development benefits from the spaceport to Doña Ana County.

In addition, Whitesides said Virgin Galactic is nearing completion of constructing some support infrastructure at the spaceport for its operations.

Now, the company's flight testing program is based in Mojave, California. But plans call for its operations to shift to New Mexico with the start of suborbital flights. Virgin Galactic already has begun ramping up staffing in southern New Mexico. Some 40 to 45 staffers are already employed here, and between 100 and 200 are expected to be on board in New Mexico for the start of space tourism flights, according to Whitesides. He said privatized human spaceflight has reached a "tipping point" and is at "an exciting moment now.

Taking payloads to space

ISPCS speaker Eric Stallmer is president of the Commercial Spaceflight Federation, a nonprofit that advocates for companies, universities and spaceports that are involved in commercial spaceflight. He said the foray into privately funded and developed spaceflight, such as Virgin Galactic and SpaceX's ventures, is helping to drive down the cost of taking payloads to space. Historically spaceflight has been a government-driven and -funded activity.

Those lower costs are opening the door to new clients who never could have afforded to have people and payloads reach space previously, Stallmer said. And he believes that will spark the public's widespread interest.

"It's going to ignite this great sense of excitement to be able to go into space," said Stallmer, who's based in Washington, D.C.

The symposium kicked off with a few events on Tuesday but got underway in earnest on Wednesday. Thursday is the last day of the 2018 event.

Diana Alba Soular may be reached at 575-541-5443, dalba@lcsun-news.com or @AlbaSoular on Twitter.